MM cells impair osteoblast differentiation via secretion of Dickkopf‐1 and IL3; activate osteoclasts by VEGF secretion; and induce angiogenesis by secreting VEGF, HGF and other cytokines. MM cells inhibit T‐cells by TGFβ and IL10 creating an immunosuppressive environment. The modified BM niche supports MM growth, disease progression and chemoresistance via a combination of secreted cytokines, chemokines and an altered extracellular matrix. Here, DKK1 is linked to Miyoshi myopathy.